Duchenne Muscular Dystrophy

Reports from the MHC data base

Codes

ICD-10: G71.0ORPHA: 98896

Estimated occurrence

30:1 000 000 inhabitants. Only affects boys.

Etiology

A shortage of the protein dystrophin, which stabilizes muscle fibers. This lack of dystrophin results in deterioration of muscular fiber. Duchenne muscular dystrophy is an Xlinked inherited disorder. Female carriers have no symptoms. One-third of all cases are spontaneous mutations.

General symptoms

Symptoms normally present around the age of three. The child develops a waddling gait, has difficulty running, jumping and getting up off the floor. The thoracic girdle, the pelvic and the musculature of the back all become progressively weak. Upper arms and thighs are affected earlier than lower arms and calves. Curvature of the lumbar region develops. These boys generally stop being able to walk around the age of 10 to 12. Impaired cardiac function often develops. Muscular weakness increases over the years. Many individuals develop contractures and scoliosis. The respiratory musculature is weakened, and lung function reduced. Malignant hyperthermia has been reported and should be considered when treatment under general anesthesia. There may be concentration problems and learning disability.

Orofacial/odontological symptoms

Weakness of the main muscles used for chewing, the facial muscles and the tongue. Malocclusions develop successively owing to muscular weakness and, in some cases, to changed morphology of the tongue (enlarged tongue due to muscular atrophy). The jaws increase in width, more in the lower jaw than in the upper, which often results in a posterior cross-bite. Later a lateral open bite may appear and later on a frontal open bite can be seen. Reduced muscular strength and endurance of the chewing muscles in combination with lack of occlusal (bite) contact may result in difficulties masticating food. In late stages of the disease, swallowing difficulties often develop. The mouth opening capacity can be reduced.